Add GITHUB_TOKEN to avoid rate limits

[iffy]

Fixes iffy/install-nim#8

If you'd like to review what changed between v3.1 and v3.2.0 of install-nim, here's the diff: iffy/install-nim@v3.1...v3.2.0

[Araq]

CIs is completely red with this change. Strange.

[iffy]

I don't understand why the tests are failing. It looks like only one test ran (the others were canceled at the first failure): https://github.com/nim-lang/nimble/pull/902/checks?check_run_id=1963277877 And the failure is for something that happens after install-nim is done.

1. Would you like all tests to continue running even if one test fails? I can make that change if you'd like.
2. Maybe the tests behave differently when GITHUB_TOKEN is set?

[dom96]

Well, it was broken in d13f3b8

It's clearly caused by this change, here is the error:

/home/runner/work/nimble/nimble/tests/nimbleDir/pkgs/nimble-#head/nimblepkg/common.nim(70, 21) Error: cannot open file: ../../nimble.nimble

I know it's annoying having to update the version in all 2 files... but at least it doesn't lead to annoying failures in CI. Can we revert this change?

[Araq]

I know it's annoying having to update the version in all 2 files... but at least it doesn't lead to annoying failures in CI. Can we revert this change?

Not if I can help it, I hate having to update the version in two places.